M5.6 Earthquake 37 km NW of Añatuya, Argentina — December 27, 2025
2025-12-27 10:40:49 UTC (2025-12-27) · approx. 6:40 AM UTC-4 local
On December 27, 2025 at 10:40 UTC, a magnitude 5.6 deep-focus earthquake struck 37 km NW of Añatuya, Argentina, at a depth of 593.4 km and coordinates -28.2562°, -63.1342°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 100 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 482, placing it among routine seismic activity. The nearest populated place is Herrera (population 0).
Physical scale: An earthquake of magnitude 5.6 releases seismic energy equivalent to roughly 4 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 4.4 km — a useful intuition for the size of the slip patch on the fault.
Nearest Populated Places
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Population exposure (USGS PAGER)
Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.
| Shaking intensity (MMI) | Description | Population exposed |
|---|
Earthquake Details
-63.1342°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 5.6 earthquake near Añatuya, Argentina?
The magnitude 5.6 earthquake that struck 37 km NW of Añatuya, Argentina on December 27, 2025 at 10:40 UTC had a depth of 593.4 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -28.2562°, -63.1342°, which is 37 km NW of Añatuya, Argentina. The nearest populated place is Herrera (population 0).
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.6 earthquakes can continue for days to weeks and gradually diminish over time.
What should I do after an earthquake?
If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.
Authoritative source: USGS event page (event ID: us7000rl1p). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, December 27, 2025). M5.6 Earthquake 37 km NW of Añatuya, Argentina — December 27, 2025. Retrieved May 23, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000rl1p/